I have a shallow well with a new external pump/tank assembly that I just installed. The well was in my house when I moved in-there was an old pump/tank assembly that didnt work. When I turn on the new pump, it pumps for only a few seconds, then goes down to a trickle before stopping completely. I have primed the pump. There is no pressure when activating the pump, except for a few pounds when you first turn it on. I do not know anything about wells, but some of my neighbors have the same ones as I do. One neighbor told me he poured some muriatic acid down the well because the tip was clogged. How do I even know if this well is still good? Is there anyway to check?

Help!!!